1. Field of the Invention
This invention relates to methods, compositions and kits for simultaneously detecting one or more analytes such as drugs in a sample.
The clinical diagnostic field has seen a brad expansion in recent years, both as to the variety of materials of interest that may be readily and accurately determined, as well as the methods for the determination. Convenient, reliable and non-hazardous means for detecting the presence of low concentrations of materials in liquids is desired. In clinical chemistry these materials may be present in body fluids in concentrations below 10xe2x88x9212 molar. The difficulty of detecting the presence of these materials in low concentrations is enhanced by the relatively small sample sizes that can be utilized.
Over the last decade, testing for drugs of abuse has become commonplace. This testing is not only for the monitoring of criminal offenders and drug addicts, but employers also use it for the screening of workers. Most multi-analyte assays are heterogeneous, have poor sensitivity and poor dynamic range (2to 100-fold difference in concentration of the analytes is determined) and some require the use of sophisticated instrumentation.
High volume screening for drugs of abuse is currently carried out commercially by conducting a series of individual homogeneous immunoassays (EMIT or FPIA). A cut off level is set for each drug, which is used to establish whether a particular result will be defined as positive or negative. It is necessary for testing laboratories to handle separate reagent sets and carry out separate assays for each of the commonly abused drugs in every sample. Typically, the presence of as many as six drugs must be determined.
Among those homogeneous assays that have been used commercially or are particularly good candidates for drug screening, EMIT(copyright), CEDIA(copyright), FRAT(copyright) and SLFIA have the property of having an increase in signal with an increase in drug concentration. However, because of sensitivity problems or problems intrinsic to these methods, assays for low concentration analytes can have relatively high negative signals, sometimes more than 50% of the maximum possible signals. Combined assays, therefore, show a serious loss in sensitivity. Moreover, induced luminescence assays have decreased signals (fluorescence polarization and chemiluminescence, respectively) with increasing drug concentration and are, therefore, poor candidates for a combined drug assay.
Because of the resultant increase in testing, a market has opened up for xe2x80x9cquick xe2x80x9cYes or Noxe2x80x9d tests.xe2x80x9d These are assays that can test qualitatively for drugs of abuse. Many of the xe2x80x9cquick testsxe2x80x9d which have been described are designed to be used as xe2x80x9con sitexe2x80x9d assays, [EZ-SCREEN(trademark) (Editek Inc., Burlington, N.C.), ONTRAK(trademark) (Roche Diagnostics Systems, Inc., Branchburg, N.J.), Triage(trademark) (Biosite Diagnostics, San Diego, Calif.) and ONTRAK TESTCUP-5(trademark) (Roche Diagnostic Systems, Somerville, N.J.)] and a few of them are able to test for more than one drug in a single assay (Triage(trademark) and ONTRAK TESTCUP-5(trademark)). In these multi-analyte systems, if any one of the tested drugs is over a threshold limit, a positive result is obtained. Such positive results must then be confirmed by an unrelated method.
2. Brief Description of the Related Art
U.S. Pat. No. 5,661,019 (Oh, et al.) discloses trifunctional conjugates having three chemical moieties attached through a spacer moiety.
U.S. Pat. No. 5,567,627 (Lehnen) describes method and composition for the simultaneous and discrete analysis of multiple analytes.
U.S. Pat. No. 5,340,716 (Ullman, et al.) describes an assay method utilizing photoactivated chemiluminescent labels.
Photoactivatable chemiluminescent matrices are described in U.S. Pat. No. 5,709,994 (Pease, et al.).
One aspect of the present invention is a method for determining the presence of one or more analytes in a sample suspected of containing any of a plurality of the analytes. A combination is provided comprising in a medium (i) the sample, (ii) a binding partner for each of the analytes, (iii) for each of the analytes, a first reagent comprising a member of a signal producing system, a ligand and an analyte analog, and (iv) a second reagent comprising a binding partner for the ligand. The binding of the second reagent to the ligand alters the amount of signal produced by the member of a signal producing system. The amount of the signal is determined and is related to the presence of one or more of the analytes in the sample. The method may be homogeneous or heterogeneous. In a preferred embodiment, a predetermined increased amount of signal is produced if one or more of the analytes are present in the sample.
Another embodiment of the present invention is a method for determining the presence of one or more analytes in a sample suspected of containing any of a plurality of the analytes. The sample and a binding partner for each of the analytes are combined in a medium. A first reagent is added to the combination for each of the analytes. The first reagent comprises a member of a signal producing system, a ligand and an analyte analog. A second reagent comprising a binding partner for the ligand is added to the combination. The binding of the second reagent to the ligand alters the amount of signal produced by the member of a signal producing system if one or more of the analytes are present in the sample. The medium is examined for the amount of the signal, which is related to the presence of one or more of the analytes in the sample.
Another embodiment of the present invention is a method for simultaneously determining the presence of one or more drugs in a sample suspected of containing any of a plurality of the drugs. The sample and an antibody for each of the drugs are combined. Then, to this combination is added, for each of the drugs, a first reagent comprising a first label, a small molecule and a drug analog. A second reagent is added to the combination. The second reagent comprises a second label and an antibody for the small molecule. The first label and the second label interact in close proximity to produce a predetermined increased amount of signal if one or more of the drugs are present in the sample. The medium is examined for the amount of the signal. An increased amount of signal is related to the presence of one or more of the drugs in the sample above a predetermined cut-off level.
Another embodiment of the present invention is a kit for determining the presence of one or more drugs in a sample suspected of containing any of a plurality of the drugs. The kit comprises in packaged combination (i) an antibody for each of the drugs, (ii) for each of the drugs, a first reagent comprising a first label, a small molecule and a drug analog, and (iii) a second reagent. The second reagent comprises a second label and an antibody for the small molecule. The first label and the second label are capable of interacting in close proximity to modulate a signal if one or more of the drugs are present in the sample.